Shader doesn't affect entire Object
That's the reflection of the table. Try hiding the table/plane object and take a look.

Edit to address followup question;

... Technically, yes, you can disable the table in the reflection. Start by switching to the Cycles rendering engine (and make sure GPU is selected if you have a GPU capable of supporting Cycles);



In the Object Properties, Under Visibility -> Ray visibility, uncheck "Glossy";



The result;



It should be noted, though, that this will produce a highly unrealistic result in your final scene.